When harvesting agricultural crop on a field it is established practice that a harvesting machine loads a transport vehicle, which moves alongside the harvesting machine, with harvested crop. A loading container of the transport vehicle which is, for example, a tractor with a trailer or a truck, when travelling is loaded with the harvested crop by means of a discharging device of the harvesting machine, for example in a forage harvester via a discharge shaft and in a combine harvester via an ejection duct. The discharging device is generally fastened rotatably to the harvesting machine about a vertical axis and is pivotable between a resting position in which it is oriented approximately parallel to the longitudinal axis of the harvesting machine and an operating position in which it extends transversely to the direction of travel of the harvesting machine. Additionally, the height of the end of the discharging device on the discharge side may be varied, as may be the position of an ejection flap which defines the angle at which the harvested crop is discharged.
In discharging devices which may not be adjusted in their discharge position, as used conventionally in combine harvesters, the driver of the transport vehicle has to ensure that the loading container is filled uniformly and fully by gradually positioning different points of the loading container below the discharging device. This task is relatively demanding and tiring as losses of harvested crop due to harvested crop falling onto the field have to be avoided.
With adjustable discharging devices, as used conventionally in forage harvesters, in the simplest case the position of the discharging device is manually controlled by the driver of the harvesting machine, for which input devices are available to the driver in the cab, which activate actuators used for adjusting the discharging device. In this connection, the driver of the harvesting machine has to ensure that the entire loading container of the transport vehicle is sufficiently filled, which is carried out by successively aligning the discharging device with different points on the loading container. Should the transport vehicle deviate from its desired position forward or backward or to the side, the position of the discharging device has to be manually readjusted. In this connection, it may be regarded as a drawback that the control of the position of the discharging device takes up a considerable portion of the attention of the driver which results in tiring work for the driver of the harvesting machine.
Published German patent application, DE 44 03 893 A1 discloses a forage harvester comprising a discharging device, at the ends thereof on the discharge side a distance meter being attached, which detects the level of the harvested crop in the loading container. As soon as the harvested crop has reached a predetermined level, the discharging device is adjusted until the entire loading container is filled. In this case, the process is automated which substantially relieves the burden on the driver of the harvesting machine but which requires a costly distance meter.
In European patent application EP 1 219 153 A, it has been proposed to move the loading container automatically or manually relative to the harvesting machine into a position in which it may be filled. In fixed discharging devices (combine harvesters), information about the position of the discharging device is transmitted by means of a remote data transmission device to the transport vehicle and the position of the transport vehicle adapted, whilst movable discharging devices (forage harvesters), based on data regarding the position of the loading container and its own position, are automatically moved into a position in which they fill the loading container. If the driver identifies that a region of the loading container has been sufficiently loaded with harvested crop, and now a different region has to be filled, the position of the discharging device is manually altered by the driver of the harvesting machine. If the range of movement of the discharging device is no longer sufficient in order to reach insufficiently filled regions of the loading container, the relative position of the transport vehicle to the harvesting machine is automatically altered, which may also take place in the opposing direction to the discharging device.
Accordingly, the discharging device is automatically aligned continuously with a specific position on the loading container. The driver of the harvesting machine is, however, not relieved of the task of monitoring the cone of bulk material of the harvested crop collecting on the loading container and, if required, moving the discharging device into a new position.
European patent application EP 1 645 178 A proposes to guide the discharging device of a forage harvester along a defined geometry, which may be a straight line or curved path extending in the central longitudinal direction of the loading container. Also in this case, the position of the discharging device is changed by an input from the operator. Relative to the disclosure of EP 1 219 153 A the operator is merely relieved of the choice of a new position of the discharging device.
In the publications “Assistenzsystem zur Überladung landwirtschaftlicher Güter” (“Assistance System for transferring Agricultural Crops”) by G. Wallmann and H. H. Harms, Landtechnik 2002, pages 352 and 353, and “Häckselgut automatisch Überladen” (“Automatic Transfer of Chopped Material”) by A. Böhrnsen, Profi November 2006, pages 84 to 86, it is proposed to implement a loading strategy by means of the discharging device which effects a uniform and complete loading of the transport trailer by an alignment with different target areas in a clocked manner. To this end, the discharging device and its ejection flap may be guided in a zig-zag pattern, or alternatively only the ejection flap is continuously pivoted to and fro, whilst the transport vehicle is gradually moved further forward or backward by its driver. In this case, monitoring of the loading container is no longer required by the driver, as the control of the discharging device is carried out fully automatically. However, it is not taken into account by the set loading strategy that the most appropriate filling method in each case may also depend on the type of transport vehicle. Thus trucks with driven rear axles initially have to be loaded above the rear axle, whilst in contrast semitrailers have to be initially loaded in the front region of the trailer in order to ensure the traction capacity. In the prior art, the type of terrain is also not considered which may also have an effect on the best loading strategy in each case where there are lateral inclinations or inclinations present in the direction of travel.